Barbara Corcoran's ex-boyfriend dumped her for her secretary — and it was the best thing to happen to her career

He said she'd never succeed without him — she proved him wrong. Barbara Corcoran pictured. Jamie McCarthy/Getty Images

Barbara Corcoran is a real-estate mogul and a "Shark Tank" star.

Corcoran's ex-boyfriend and ex-business partner left her for her secretary in the 1970s.

The ex told her she'd never succeed without him.

That helped motivate Corcoran to launch her own real-estate company and become wildly successful.

"You know," Barbara Corcoran's ex-business partner and ex-boyfriend told her soon after they split up, "you'll never succeed without me."

Anyone else might have felt those words sting and then, eventually, brushed them off. But for Corcoran, "It just hit me in the gut and I felt that fever in my body like, 'I'll be damned if you ever see me not succeed.' I felt like I would kill not to let that thing happen."

Four decades later, Corcoran is a real-estate mogul and a star investor on the ABC series "Shark Tank." That is to say, she's more than proved that ex-boyfriend and ex-business partner wrong.

On an episode of Business Insider's podcast, "Success! How I Did It," Corcoran told US editor-in-chief Alyson Shontell how her relationship with that ex-boyfriend, Ramone Simone, changed her life.

Corcoran was a waitress at a diner when she met Simone. Early in their relationship, Simone suggested she go into real estate. Corcoran worked as a receptionist at a real-estate agency; Simone suggested they start a real-estate company together.

He gave her $1,000 and said she could take 49% of their business, which was called Corcoran-Simone company.

Seven years later, Corcoran told Shontell, Simone came home and announced — surprise! — he was going to marry Corcoran's secretary.

After the breakup, Corcoran took a level-headed approach to dissolving the Corcoran-Simone company. She told Shontell: "I put the rules down. I said, 'This is how we're going to end the business. You picked the first person [her secretary]. I'll take the second.' We divide our receivables, we divide our cash — the little we had."

Corcoran was savvy about starting the Corcoran Group

When Corcoran was starting her real estate company, she placed her very first business advertisement in The New York Times. She asked her old boss at the real-estate agency if she could have one of his listings to advertise. It was the apartment next to the super's, and it had an L-shaped living room with a small bedroom, "like every other apartment in New York."

Corcoran wanted to make her ad stand out. And so she asked if she could put up a fake wall in the living room and wrote: "1 BR Plus Den: 340."

She told Shontell, "It fit on one line, right margin, and I probably got 80 phone calls that next morning. … Within the first two days I had a check for $340."

Perhaps the sweetest revenge she exacted on Simone right after the breakup? She told Shontell:

"I moved two floors above him in the same building. I went immediately to my landlord to ask for a new lease on another space and it was a tough market. He happily gave it to me and it was cheaper than my other lease by a few hundred dollars a month. And I loved getting out of that elevator with Ramone Simone and his new wife every day and saying, 'Sorry, I'm going up.'

"Stupid ego lifts that you do in life, right! But somehow that made a difference. If I was below him, psychologically it would not have been good."